ZDaemon 1.08.07 and earlier allows remote attackers to cause a denial of service (daemon crash) via a crafted type 6 command, which triggers a NULL pointer dereference.
Buffer overflow in the is_client_wad_ok function in w_wad.cpp for (1) Zdaemon 1.08.01 and (2) X-Doom allows remote attackers to execute arbitrary code via a long filename argument.